A. Field of the Invention
This invention relates to the field of art of semiconductor bistable flip-flop circuits.
B. Prior Art
Much prior work has been done in the field of bistable flip-flop circuits made of semiconductor field effect transistors (FET). These transistors have been used in complex monolithic substrates or chips. An important economic consideration in making chips has been minimizing the area on the chip taken up by each individual circuit by minimizing its number of circuit elements. However, prior stable flip-flops which have been designed have left much to be desired in that they have required a substantial number of individual transistors. For example, prior CMOS stable flip-flop circuits with reset have required 18 transistors in order to provide proper gating functions. Other prior stable flip-flop circuits have required two pairs of cross-connected inverters with each pair having its own transmission gate which was necessary to gate the cross-connection feedback signal and in this way to change the stable state.
Accordingly, an object of the present invention is to reduce the numbers of transistors used in a bistable FET flip-flop circuit.